Spectrally sensitized silver halide photographic emulsion

ABSTRACT

A photographic silver halide emulsion which comprises silver halide and the combination of at least one sensitizing dye represented by the general formula (I)   wherein A2 represents a hydrogen atom or a lower alkyl group; Z3 represents an atomic group required for forming a benzoselenazole nucleus; Z4 is an atomic group required for forming a benzothiazole nucleus or a benzoselenazole nucleus; R3 and R4 each represent a lower alkyl group; X2 is an acid anion; and q is 1 or 2, q being 1 when said latter dye constitutes a betaine structure with R3 or R4.   wherein A1 represents a lower alkyl group; Y1 and Y2, which may be the same or different, each represents a sulfur atom or a selenium atom; Z1 represents an atomic group required for forming a naphthol ring; Z2 represents an atomic group required for forming a naphthol ring or a benzene ring; R1 and R2 each represent a lower alkyl group, at least one member selected from the group consisting of R1 and R2 being an alkyl group substituted with a sulfo radical; X1 is an acid anion; and p is 1 or 2, p being 1 when said dye has a betaine structure; and at least one sensitizing dye represented by the general formula (II)

United States Patent [191 Shiba et a1.

[ 1 SPECTRALLY SENSITIZED SILVER HALIDE PHOTOGRAPHIC EMULSION [75] Inventors: Keisuke Shiba; Akira Sato, both of Minami Ashigara-Kamigun, Kanagawa, Japan [73]. Assignee: Fuji Photo Film Co., Ltd., Minami Ashigara-shi, Kanagawa, Japan [22] Filed: Sept. 10, 1971 [2]] App]. No.: 179,391

[30] Foreign Application Priority Data Sept. 10, 1970 Japan 45-79515 [52] US. Cl 96/124, 96/131, 96/132, 96/137 [51] Int. Cl G03c 1/14 [58] Field of Search 96/124 [56] References Cited UNITED STATES PATENTS 3,459,553 811969 Walworth 96/124 3,573,920 4/1971 Hiller 96/124 3,667,960 6/1972 Shiba et al. 96/124 3,679,428 7/1972 Shiba et al. 96/124 3,681,080 8/1972 Nakazawa et a1 96/124 Primary Examiner-J. Travis Brown Attorney, Agent, or Firm-Sughrue, Rothwell, Mion, Zinn & Macpeak [57] ABSTRACT A photographic silver halide emulsion which comprises silver halide and the combination of at least one sensitizing dye represented by the general formula (1) which may be the same or different, each represents a sulfur atom or a selenium atom; 2 represents an atomic group required for forming a naphthol ring; Z represents an atomic group required for forming a naphthol ring or a benzene ring; R, and R each represent a lower alkyl group, at least one member selected from the group consisting of R and R being an alkyl group substituted with a sulfo radical; X is an acid anion; and p is 1 or 2, p being 1 when said dye has a betaine structure; and at least one sensitizing dye represented by the general formula 11) 5 Claims, 3 Drawing Figures [451 Apr. 30, 1974 PAI EmPR30-|9M 3308;008-

' WAVELENGTH m WAVELENGTH my) FIG} 400 440 480 520 560 600 v 640 680 720 WAVELENGTH my) A BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to spectrally sensitized silver halide photographic emulsions, and more particularly to superpanchromatically sensitized silver halide photographic emulsions obtained by employing a combination of at least two selected sensitizing dyes.

2. Description of the Prior Art An object of the present invention is to provide a photographic light-sensitive element having a high sensitivity extending uniformly over the wavelength range of 400 mp. to 700 mp. In order to sensitize the element over this wide wavelength range, generally, at least two sensitizing dyes in combination are employed and in this case, it is usual that the maximum sensitivity obtained by employing a combination of at least two sensitizing dyes is lower than that obtained by employing each dye alone. However, a high spectral sensitivity can be superadditively obtained by the use of more than two sensitizing dyesin specific combination, and this phenomenon is known assupersensitization.

The object of the present invention will be accomplished by finding a combination of a group consisting of sensitizing dyes particularly giving a supersensitizing effect and imparting a high sensitivity over a wavelength range of from 680 my. to 550 mu.

Generally speaking, a dye having a spectral absorption and which sensitizes an emulsion over a long wavelength region has many disadvantages as compared to another dye having its spectral absorption and sensitization in a short wavelength region. For example, these disadvantages are such that the desensitization with respect to intrinsic absorption of light of a silver halide emulsion is more remarkable, the efficiency of sensitization is liable to be reduced, and fog is also likely to occur.

Therefore, although the maximum absorption wavelength of an isolated molecule of the dye itself relates to a short wavelength, it is considered that such a dye having an absorption peak in the longer wavelength region, when it is adsorbed on the above-described silver halide grains, particularly a dye which forms a J-band when adsorbed on the silver halide grains in the emulsion, is advantageous for the object of the present invention.

From the viewpoint of the J-band-forming function, a severe selectivity is required for combining the sensitizing dyes. The dye which has the sensitivity peak in the longest wavelength region in a group of dyes to be combined must be most likely to form a J-band, and in this case, the J-band must not be destroyed by the other combined dyes or other additives. For another dye, a suitable forming function of the J-band is required, that is, in the case where the forming function is too remarkable, there is a tendency such that a supersensitizing function is hard to achieve and a uniformly high spectral sensitivity distribution is also hard to obtain.

For these various reasons as mentioned above, it is considered in general that the deduction of the selective combination of groups of dyes having supersensitization on the basis of mere apparent similarities of their chemical structural formulae is very difficult.

SUMMARY OF THE INVENTION It was, however, found that the object of the present invention and an improvement over the disadvantages of the prior art as mentioned above could be accomplished by incorporating a combination of at least one carbocyanine dye represented by the following general formula (I) and at least one sensitizing dye represented by the following general formula (II) into a silver halide emulsion:

in which A represents a lower alkyl group, such as methyl, ethyl or n-propyl; Y and Y which may be the same or different, each represents a sulfur atom or a selenium atom; Z represents an atomic group required for forming a naphthol ring; Z represents an atomic group required for forming a naphthol ring or a benzene ring, each of which may be substituted by, for example, a lower alkyl group such as methyl and/or ethyl, a halogen atom such as chlorine or bromine, a hydroxy group, an alkoxy group, an alkoxycarbonyl group, a carbonyl group or a carboxyl group; R and R represent lower alkyl groups (such as methyl, ethyl, npropyl, allyl, or substituted alkyls having a sulfo radical such as sulfoethyl, sulfopropyl, a-sufobutyl and S-sulfobutyl), at least one member selected from-the group consisting of R and R being a substituted alkyl having a sulfo radical; Xf is an acid anion; and p is l or 2, p being 1 when a betaine structure is formed;-

in which A represents a hydrogen atom or a lower alkyl group; Z represents an atomic group required for forming a benzoselenazole ring nucleus; 2., represents an atomic group required for forming a benzothiazole ring nucleus or a benzoselenazole ring nucleus, either of which may be substituted or unsubstituted, respectively (for example, the heterocyclic ring may be substituted by a lower alkyl group such as methyl or ethyl, a halogen atom such as chlorine or bromine, phenyl alkoxycarbonyl, carboxyl, hydroxyl, or alkoxy); R and R represent lower alkyl groups (such as methyl, ethyl, and n-propyl, B-hydroxyethyl, fi -carboxyethyl, a-carboxypropyl, S-carboxybutyl, B-sulfoethyl, a-sulfopropyl, a-sulfobutyl, S-sulfobutyl, 2-(3-sulfopropoxy)- ethyl, B-acetoxyethyl, sulfatoethyl and allyl); X; is an acid anion such as a chlorine, bromine, iodine, p-toluenesulfonic acid or perchloric acid ion; and q is l or 2 and, in the case of forming a betaine structure with R or R,, q is l.

BRIEF DESCRIPTION OF THE DRAWINGS FIGS. 1, 2 and 3 are spectograms of combinations of dyes shown in Example 1.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The combination which is preferred according to the present invention comprises at least one sensitizing dye of the general formula (III) and at least one sensitizing dye of the general formula (IV):

(III) wherein R and R represent the above-mentioned alkyl groups having a sulfo radical;

M wherein R R X and q have the same meaning as in general formula (II).

The sensitizing dye represented by the above general formula (I) has the following three characteristic features. That is, the first characteristic feature resides in the fact that at least one member of the two cyanine heterocyclic nuclei is a B-naphthothiazole nucleus or a B-naphthoselenazole nucleus. The second characteristic feature resides in the fact that the sensitizing dye easily forms a J-band and particularly, the maximum sensitivity thereof is between a wavelength ranging from 650 mu to 700 mu, and in the case where this second feature is satisfied, the heterocyclic ring nuclei may be substituted or unsubstituted, respectively. Furthermore, the third characteristic feature resides in the fact that at least one of R and R has a sulfo radical, the betaine structure probably being fonned with this sulfo radical, and it is, therefore, considered that the J-band is liable to be formed.

It is to be understood that the substituents are not substantially limited to those described specifically in the present specification when the above-mentioned necessary conditions are satisfied.

On the other hand, the characteristic feature of the sensitizing dye represented by the general formula (II) resides in the fact that at least one of the heterocyclic ring nuclei formed by Z, and 2,, respectively, is a benzoselenazole nucleus. In this case, as compared with that in which both of the two cyanine nuclei are benzothiazole nuclei, the supersensitizing function obtained by the combination use with the dyes represented by the general formula (I) is not only more remarkable, but also a more uniform spectral distribution of the sensitivity is obtained. In this respect, accordingly, the invention according to Japanese Patent Publication No. 4933/68 was remarkably improved.

Furthermore, when the present invention is further combined with that of Japanese Patent Publication No. 23320/69, it is advantageous for producing a photographic light-sensitive element having a high uniform sensitivity ranging from 400 mu to 700 mu of wavelength.

That is, monomethine dyes such as 2,2- quinocyanine dyes and pseudocyanine dyes, preferably of the general formula (VI), may be added to the photographic emulsion of the present invention.

wherein Z represents an atomic group required for fonning a benzene-series ring, Z represents an atomic group required for forming a quinoline-series ring, a benzthiazole-series ring or a benzselenazole-series ring, and R R X and r have the same meaning as R;,, R X and q of the general formula (II), respectively.

For example, Dye A or B as shown hereinbelow may be employed in combination with the sensitizing dyes of the present invention.

(CHzhBOa' S ooa=e on c I I zHi S Se (IIA) (mails/ 3112) 4SO3HN (JJHmsOr I CH CHzOH (HQ) A Hac- (BHZGHZOH .A (IID) Se 6H, amila 1 3 13 N Cl am y l (CH MCOOH CHzCH=CHz (III) CzH5 The sensitizing dyes represented by the general formulae (l) and (II) can be synthesized by well-known processes, for example, by referring to the specifications of U.S. Pat. No. 2,503,776, British Pat. No. 742,] 12, West German Pat. No. 1,072,765, West German Pat. No. 1,163,671 and US. Pat. No. 3,177,210, respectively, the dyes can be easily synthesized by those skilled in the art.

The sensitizing dye employed for the present invention is dissolved in an aqueous solution or water soluble organic solvent, for example, methanol, ethanol, acetone, methyl cellosolve, or pyridine and is mixedly or separately added to a silver halide emulsion.

On one hand, the sensitizing dye may be dissolved or dispersed in an oil having a solubility of less than 10 percent with respect to water, the resulting dispersion or solution being added to the emulsion. For the dissolution of the sensitizing dye, ultrasonic vibration may be adopted. The amount added, and order for adding the sensitizing dye, or the timing of preparing the emulsion to be added, and the method for the addition thereof can be suitably changed in accordance with its purpose. In general, it ispreferable that the amount, to be employed, of the sensitizing dye of the general formula (l) or (11) is within a range for from 1 X 10? mol to X mol per 1 mol of silver halide. Furthermore, it is preferable that the amount to be employed of the dye represented by the general formula (11) with respect to the dye represented by the general formula (1) 8 terephthalate film, a polycarbonate filrrf o ther plastic films, a glass plate, baryta paper, a resin-coated paper, and synthetic paper in accordance with its purpose.

The following examples will more specifically illustrate the present invention and other objects of the present invention will also be understood thereby.

EXAMPLE 1 One kg of a silver chlorobromide emulsion (Br content; l7 mol percent) which was prepared in accordance with an ordinary process and chemically sensitized was warmed to melt it.

The sensitizing dye represented by the general formula (1) or (11) was added to the emulsion in an amount (added in the form of a dyemethanol solution) in the concentration shown in the Table l, and was sufficiently agitated.

A methanol solution of each comparative dye C and D, having a predetermined concentration, was added in a predetermined amount to a corresponding silver halide emulsion and was sufficiently agitated, respectively.

Each of the resulting mixtures was maintained for 10 minutes after adding each solution thereto at a temperature of C, an anionic wetting agent and a hardening 'agent were added thereto, and the thus-obtained mixture was applied onto a film and dried, to thereby obtain samples of a light-sensitive element.

Each of the resulting light-sensitive elements was cut into two pieces, one of which was subjected to wedge exposure through aNoiit-Tiyiiowrfnr (manufactured by Fuji Photo Film Co., Ltd.) by employing a sensitometer having a light source of 5400K obtained by applying a DG (Davis-Gibson) converting filter to a 5 light source of a color temperature of 2666K. The

other portion of the samples was subjected to exposure by employing a GR-2 type (reflex type diffraction lattice) spectrograph manufactured by Narumi & Co.

By employing the following developer, these samples were developed for 4 minutes at a temperature of 20C and further were fixed and washed with water to thereby obtain strips, respectively. Composition of the Developer.

is within a range of from 1:10 to 10:4, in molar ratio. H w M H H m Wm.

WT w m i l I Q H Metol 2 g The amount to be added of the monomethme dye is Anhydrous Sodium sulme 40 g within the range of from 10 mol to 10 mol per 1 mol q i ne 4 g of the dye of the general formula (1). 2 qh Mmwhydrate s As the silver halide emulsions employed for the pres- ,',f, e 1 g ent invention, there are silver iodobromide, silver bromide, silver chlorobromide, silver chloroiodobromide, "a Y and the like, produced by an ordinary method, and a The thus obtained developer was diluted with water chemical sensitizing method according to a publicly to twice the amount thereof and the resulting solution known method is applied to these emulsions. was employed for developing the above described Furthermore, antifoggants, stabilizing agents, chemistrips. cul sensitizers, development accelerators, surface ac- As a result of measuring the densities of the samples, tive agents, film quantity reforming agents, or photoyellow filter sensitivities (Sy) and fog were obtained graphic dyestuffs and, if necessary, color couplers may and these results are shown in Table 1 by the correalso be added to the silver halide emulsion. .sponding relative values thereof. The FIGS. 1, 2 and 3 The obtained emulsion is applied onto a suitable sup- 7 inclusjvg are refgred to under the column heading port such as a cellulose derivative film, a polyethylene Remarks in Table 1.

.. v m." t t a I XB I:E. 1.. 1. .1

No. Dye Amount added (mol Dye Amount added (mol Maximum sensitivity Sy Fog Remarks concentration in concentration in wavelength mu methanol solution) methanol solution) 1' (IA) 80 (5 |0-) 685 66 0.13 I60 685 66 0.15 320 685 70 0.23 (llA) ROHXIO) 600 91 0.13

TABLE l Continued No. Dye Amount added (mol Dye Amount added (mol Maximum sensitivity Sy Fog Remarks concentration in concentration in wavelength mu methanol solution) methanol solution) I 160 640 120 0.13 320 640 132 0.13 (IA) 160 (11A) 160 680 150 0.15 2 (11B) 80 (lX10"-) 610 100 0.13 160 610 125 0.14 320 645 132 0.15 (IA) 160 (11B) 160 675 160 0.15 3 (1B) 80 (5X10) 600 66 0.14 160 675 79 0.15 320 675 85 0.20 (11C) 80 (1X10') 600 95 0.13 160 600 100 0.13 320 645 100 0.15 (113) 160 (IIC) I60 670 125 0.14 4 (1C) 80 (5Xl0) 680 50 0.13 160 680 50 0.13 320 680 32 0.20 (11D) 80 (1X10") 595 91 0.13 160 640 100 0.13 6. EAQLQ-J. l i (1C) 160 (11D) 160 675 5 0.14 5 (ID) 80 (5Xl0) 675 91 0.13 160 680 110 0.13 320 680 79 0.15 (11E) 80(1X10) 640 63 0.13 160 655 63 0.14 320 655 80 0.15 (ID) 160 (11E) 160 675 159 0.15 6 (IE) 80 (5 l0) 670 35 0.12 160 675 0.12 320 675 0.13 (11 l) (5X10) 640 91 0.13

7 (C) 160 (5 l0) 600 32 3. I Q) 8 (D) 160 (5Xl0 600 100 L). I iii) (1E) 160 (D) 160 670 112 0.13 iv) (15) 160 (I1 I) 160 673 0.13 v) No. Dye Amount added (mol Dye Amount added (mol Dye Amount added (mol Maximum Sy Fog concentration in concentration in concentration in Sensitivity methanol solution) methanol solution) methanol solution) Wavelength mu 9 (IA) (5X10") (11A) 160 (1Xl0") A 40(1X10) 680 178 0.15 10 (1A) 160 (11A) 160 B 40 680 158 0.15

i) corresponding to curve 2 in FIG. 2 ii) corresponding to curve I in FIG. 1 iii) corresponding to curve 3 in FIG. 2 iv) corresponding to curve 5 in FIG. 3 v) corresponding to curve 4 in FIG. 3

EXAMPLE 2 developed by employing the following color developing Instead of the emulsion employed in Example I, 1 Kg of a silver iodobromide emulsion (1" content; 4 mol percent) was employed and the coloring matters were similarly added thereto, respectively.

To the resulting mixture, 200 cc of a 5 percent aqueous alkali solution of an incorporatedtype cyan coupler having the following structural formula was added and agitated. Then, the emulsion was neutralized with citric acid to adjust the pH to a value of 6.5, thereafter, the emulsion was applied onto a film as in Example 1 and was dried.

In accordance with Example 1, the resulting light-- ens ti e QEEQHEMELQEHFJSEWEL (Q1111QSPPEQGFPSI as ptfgfl mii itqsata tqmgsetsts f 2291-.

Composition of the color developingagent N,N'-diethyIamino-paraaminoaniline sulfate Sodium Sulfite Sodium Carbonate Monohydrate Hydroxylamine Hydrochloride -Potassium Bromide Water to make 1 The results are indicated in Table 2. From the above descriptions, the details of the present invention will be understood.

. 1, s TABLE 2 No. Dye Amount added (mol Dye Amount added (mol Wavelength Sy Fog concentration) concentration) mu 11 (1A) 20 (5Xl0") 680 80 0.15 40 680 95 0.15 80 680 91 0.13 (11H) (lXl0") 670 91 0.13 40 670 100 0.14 80 670 95 0.15 (1A) 20 40 673 250 0.14 12 (1G) 20 (5Xl0") 670 91 0.13 40 670 96 0.13 80 670 100 0.14 (11F) 20(1X10) 645 100 0.13 40 645 l 12 0.14 80 645 100 0.13 (1C) 40 (11 H) 40 650 125 0.14

What we claim is:

l. A superpanchromatically sensitized photographic silver halide emulsion which comprises silver halide and the combination of at least one sensitizing dye pr fint stmt a snie istm le,

wherein A represents a lower alkyl group: Y and Y which may be same or different, each represents a sulfur atom or a selenium atom; Z represents an atomic group required for forming a naphthol ring; Z represents an atomic group required for forming a naphthol ring or a benzene ring; R and R each represent a lower alkyl group, at least one member selected from the group consisting of R and R being an alkyl group substituted with a sulfo radical; X, is an acid anion; and p is l or 2, p being 1 when said dye has a betaine structure, at least one sensitizing dye represented b1 the eneral tqrgal (1L a benzoselenazole nucleus; R and R each represent a wherein Z represents an atomic group required for forming a ring of the benzene series; Z represents an atomic group required for forming a ring of the quinoline series, benzthiazole series, or benzselenazole series; and R R X and r have the same meaning as R;,, R X and q in claim 1, respectively. 3-,IhQCmlllSiQlLQfJllfliHLlWhQIEllllhfijlIlQl-lllllflbfi added of the monomethine dye is within the range of from 1 X 10' mol to l X 10" mol per 1 mol of silver halide.

4. The emulsion of claim 3 wherein the amount to be added of the monomethine dye is within the range of from 10- mol to 10 mol per 1 mol of the dye of the general formula (1).

5. A photographic light-sensitive material which comprises a support having thereon the emulsion layer Qt im 1. 

2. The emulsion of claim 1, wherein said monomethine dye is represented by the following formula:
 3. The emulsion of claim 1 wherein the amount to be added of the monomethine dye is within the range of from 1 X 10 6 mol to 1 X 10 4 mol per 1 mol of silver halide.
 4. The emulsion of claim 3 wherein the amount to be added of the monomethine dye is within the range of from 10 2 mol to 10 mol per 1 mol of the dye of the general formula (I).
 5. A photographic light-sensitive material which comprises a support having thereon the emulsion layer of claim
 1. 